Permanent mold construction



Sepf, 25, 192s.

H. s. LE

PERMAENT MOLD CONSTRUCTION Filed oct. 1o, 1925 Patented Sept. 2,5, 1928.

UNITED sTATEsf PATENT AbT-"EIcE,

LEE, OF PLYMOUTH, MICHIGAN.

IERMANENT MOLD CONSTRUCTION.

Application led October This invention relates to a mold construc- I tion in which the character of the casting castingvis at all irregular the control of the .mass is capable of absorbing Q of the tions a-a which .vided with the cooling fins d so as cooling presents uite a problem. The essential object of tl is invention-is to regulate the cooling by controlling the dissipation of heat.

In the drawin s:

Fill is a vertical section through a mold in w 'ch is inserteda sand core and the molten metaL p ouredv therein.V

Fig. 2 isa vertical section through another form of casting.

Figi 3' is 'a sectional viewthrou h a mold showing another way `in which tg' casting may be' controlled.

I have illustrated in Fig. 1 a mold which is preferably formed of a pair of mold secgrooves b for su porting a sand core e within the mold. T

ese mold sections are pro- -to provide a eater' surface area for radiating heat. T e molten metal is poured into the mold, and; I 'have illustrated in Fig. 1 'a mold for casting an ordinary piston which is provided with'l theinwardly extending bosses e.. -The mass of-'metal atA this particular point 'obviously contains a greater number of B. t. u.s per square inch of surface than there would be contained in the remaining portions of the casting where the wall is relatively thinz Themold sections are preferably made of cavities being insulated that the casting will 'not stick thereto. However, these mold sections gt real hot in a couple of pourings by absor of the cast' g. p

It is the object of this invention toso construct this `mold as to absorb more heat from the casting at lcertain determined areas Where the casting is thicker,fso as to uniformly withdraw the over the entire surface. To obtain" this uniform distribution of the heat, Ibuild up on the mold sections a lar which is designated g, an this thicker portion of the mold or large a greater are each provided with the vthe molds by cast iron, the mold from the casting so ing heat out heat' fron the castingv e mass of metal, itis obvious that 1o, 1925. semi No. 61,673.

ing uniformly. a plston, to not permit an no chill to .take place. T

n mold construction it practice to provide flanges at. the top or botor both, and it may be at .this point, I provide a circumferential groove l1. about the the cross-section of the conducting material. The heat must pass through the mold adjacent the casting before it enters the large mass of metal at the to of the mold, and this Vgroove merely re uces the cr0ss-sec tional area .of the passageway. This sorbs an excess amount of heat units asf passageway with a reduced crosssectional A area does not permit the heat to be withdrawn from the casting fast enough to chill the casting at this point. The fins carried by the' mold sections for radiating heat, provide plenty of radiating surface area and we arey enabled to control the heat of controlling the radiation of heat therefrom. In my copending application, Serial N o. 51,97 3,- I show an automatic means for regulating the iow of cool air astthe mold sections, and adjacent to these 12ms, this being so regulated as to maintain a constant temperature .of the mold sections. The castinggives up its heat at a certain d, this heat; being absorbed from ated from `the mold and dissipated.

Fig. 2 shows` a mold'for a different shaped tion, andi'his heat is then radicasting. lThis mold is so designed as to provide a slight Vsurface chill about the exterior of the casting-by withdrawing the heat from the casting at a fairly rapid rate. chilled casting cannot be readily but it may be smoothed down by pntting.

- heat being caused to amount of heat from a highly desirable, of course, yto'have a uni- Aform depth of chill .so that no soft spots' in the casting willv be left uncovered after the casting'hasbeen ground. To chill the casting at a uniform depth it is necessary to cool the casting all over uniformly. Every casting presents a different problem in mold design which willveither prevent a chill from' taking place, or is arranged to chill a certain .determined area only, or to provide a uniform chill over the entire surface.

Fig. 3 shows a modified form of a means for cutting down the cross-'sectional area of vthe conducting material so as to choke back the heat.v This is obtained by drilling a number of holes m in the mold section, the pass around these holes, and obviously there is not as much room for the heat to'pass through as there was without these holes. This will achieve the same result as the circumferential grooves h by choking back the heat and preventing the mold rom absorbing an excess amount of heat from the casting. These holes may, or maynot, be filled with an insulating inaterial n such as kiesel'guhr, iire clay, or like products. It is preferable however, to fill these with kieselguhr, as then the kieselguhr, which is one of the best known heat insulating materials known, prevents the heat -from jumping across the hole. The more holes we have, of course, the more choking action We get, and it is possible to so figure and design the mold that the heat is choked back 'ust the rightamount so as to withdraw the eat from the casting uniformly.

- What I claim is:

' I In apermanent mold for casting bodies, a mold section having walls contacting withv a cast body for conducting heat 'away rom saidl casting, a portion ofthe wall sections reduced in cross sectional area at determined points to choke back the heat and reducethe heat conductivity through said wall sections.

. 2. In i a permanent mold for casting a mold section vhaving a mass of to absorb an excess determined area of 'a cast, body,'and means for restricting the ilow of heat from the casting to bodies, metal which tends vcomprises controlling such mass.,

3. In a Vperma'nent'\'mold for castin bodies, a mold section havin a mass 0I metal which tends to absor amount of heat from a determined area of a cast body and a portion having a reduced mass of metal for restricting the iow of heat from the casting to such mass to prevent the mass from absorbing an excess amount of heat from said casting at that point.

2111 EXCESS 4. In a permanent f-mold for castingbodies, a mold section having a mass oi metal which `tends to absorb an excess amount of heat from a determined area of a cast body, the wall ofv said mold section reduced in thickness at a point adjacent such mass of metal and between the mass and the casting to choke backvsome ofthe heatand prevent the mass of metal carried by said mold section from absorbing an excess amount'ofheat from said casting.

5. In 'a permanent mold for casting bodies, a mold section having walls contacting with a cast body for conducting heat away from the body, said walls provided With holes running parallel to the ace of the walls to reduce the cross sectional area thereof at determined points to choke back the heat and reduce the heat conductivity through said wall sections. y

6. A permanent mold for casting an article having variant masses at different points in 4its body, the said mold having variant masses arranged relative to the va-y riantmasses of the, article so thatv the heat of the casting is dissipated substantially uniformly. a

7 A permanent mold which comprises a molding member in which thecross section of the metal is varied to conduct the heat away from the casting faster at some parts than the others to get the predetermined effects in the casting.

8. In the art ot casting metal in permanent molds, the method of getting predetermined conditions in the cast metal, which v the dissipation of heat from the cast metal by-utilizino' a mold having walls in which the materia forming the walls is arranged to give the walls variant masses so. as to dissipate the heat wit variant degrees of rapiditfy.

" In testimony whereo I aix my signature.

` HARRY S. LEE. 

